Their Moment
by AkiraYuni
Summary: It was their moment. Their killing time. It was the story of a girl being reborn as Yukimura Aguri. She had no obligation to do anything yet still did it anyway. She vowed to save the yellow octopus teacher with her own hands. Even at the cost of her own life. OC-is-Yukimura Aguri x Koro-sensei/Former God of Death


**Their Moment**

 _ **Fandom: Assassination Classroom**_

 _ **Pairing: Koro-sensei / (1st) God of Death x OC-is-Yukimura Aguri**_

* * *

 **Henrietta**

* * *

Frankly, to tell you guys the truth, my name had been Henrietta at some point. It was all before my sudden unexpected death. My parents had died when I was five, I was an only child who had just become an orphan. I had no choice but to move in with one of my relatives but it didn't last long. I ended up being passed from one relative to another until they got sick of me and decided to simply sent me to an orphanage. It was a dark and dreary childhood. I had no friends and simply kept to myself. Most of the time, I had been regarded as "air". Someone with no presence at all, most of the times I had tried talking usually ended up with me making a bumbling mess of myself.

It was a good thing that they usually forgot about me the next day though.

My presence became known only when I wanted it to be or when someone was _really_ observant enough although the latter was mostly rare.

Despite my lack of presence, I was the curious type and loved learning. It was probably the only joy in my life. I had never noticed it before but I was pretty smart - nearing _genius_ level or maybe I really had been a genius, I didn't care much about it though. My favorite subject had been science and that was the course where I had headed. I had become a research scientist at the age of eighteen which was pretty much young for normal people's standards.

Other than that, I had also loved anime, most especially the one concerning about a yellow colored octopus teacher who went on teaching a class about life and assassination. It was a great story yet also a tragic one. I had ended up crying like a fool at the end.

But then -

\- _death happened._

I had died.

I won't tell you how since I don't really remember but I died.

Just like that.

And then another thing happened to me.

It was -

* * *

 **Reincarnation**

* * *

At first, I had a hard time wrapping my mind around the concept of reincarnation. It was a weird thing but then I got used to it. The troublesome thing was - _how come I could still remember my past life?!_ Wasn't I supposed to start as a blank state or something? I ended up sighing in the end.

My new identity was Yukimura Aguri.

Sounds familiar, doesn't it?

Yes, I had been reincarnated into this world as the woman who changed Koro-sensei's way of seeing life after he had been captured for experimentation purposes, formerly known as the God of Death, a infamous assassin.

I never cursed my fate, rather, I wanted to change it or at least change the end of Koro-sensei who had to die by his student's hand.

Was it bad that i wanted to change his fate?

 _No, not at all._ I thought.

I was happy that I had parents this time around though. It was a great blessing for me who had been an orphan during my previous life.

I had anticipated my sister's birth and became overjoyed at the thought of becoming an older sister. Just as I thought, her picked name had been Akari which meant "light." The perfect name for someone who would become an actress in the future. She would become a bright and shining star.

I swore that I would love and take care of her with my very best.

* * *

 **Plans**

* * *

I was prepared to spend my whole life trying to find a way where Koro-sensei wouldn't die in the end. I also didn't want my sister to end up becoming an avenger just because of my death though. It was due to the the case of a misunderstanding that Akari wanted revenge against the octopus teacher in the first place. So I taught her when she was old enough to understand to never assume anything until she had all the pieces in her grasp.

I knew I was no God but I still wanted to change some things in the timeline at the very least.

Perhaps when I died once again, I would no longer remember my past life. It was an interesting thought but something that would come later.

I took my intended path - _or what would have been the original Yukimura Aguri's path_ which was to become a teacher. I taught at Kunugigaoka Junior High as planned. Akari became known as a prodigal actress of course, just like in the original timeline but she was probably more sharp than what she would have been.

I then met Yanagasiwa Kotaro. He had been incredibly charming during the start as I played the submissive role. But then he became abusive once I accepted his proposal for an engagement between us. I didn't - in fact, I have never loved him from the start. I only said yes because he was an important factor in my plan.

And when the God of Death came rolling in, it was time to start my plan.

* * *

 **Endure**

* * *

When I first saw Koro-sensei, I was in awe, he really looked like someone who wouldn't dare hurt a fly. I spoke with him, wore those weird shirts that the original Aguri would have worn, befriended him and even ended up falling in love with him. I even patiently endured Yanagasiwa's beatings and abusive behavior during the whole period of time. I taught in the Class E's building but I really was never good at teaching. It was just a simple daily routine.

It all followed perfectly with the storyline, the difference perhaps being that I had longer hair than the original Aguri. Mine reached right below the waist-line, it was quite long and different, but it was what I wanted. _I was allowed to be selfish, right?_

 _Even if no one pushed me towards this direction, I could have rejected Yanagasiwa's proposal for all I knew and ended up never meeting the man who would become the yellow octopus teacher of Class 3-E._

 ** _But this was what I truly wanted._**

Shinigami-san became Shi-chan over the course of time.

I patiently endured every attack from my fiance _until..._

"Aguri, stop wasting my time! What do you want?!" Yanagasiwa yelled annoyingly as he hit me.

We were alone in a room because I wanted to ask him about something regarding the anti-matter, simply because I was curious but then he yelled. All those abusive comments and painful smacks made me growl in anger. Bloodlust I never knew which were hidden in me so long, released in the air. He fell on his butt, retreating in fear but I walked over to him in anger. I grabbed a syringe from the side and approached him, all with the intent of stabbing him.

With my weapon in hand, I had it pressed right over his neck where a major vein was located. I then smiled which probably scared him more than he could imagine at the moment.

 _"Ko-ta-ro -_ _san~"_ I murmured in a sick loving tone. "I was just about to ask you something, you know. You didn't have to hit me so hard, right?"

He nodded hesitatingly.

"If you do it again, I won't hesitate to kill you. Now be a good boy and behave, alright?"

He gulped, trembling in fear.

 _ **"Alright?"**_ I stressed, still with a blinding smile on my face.

"YES!"

And then I left, with my questions unanswered but feeling quite better than ever.

He never tried to harm me after that.

* * *

 **God of Death**

* * *

The God of Death was intrigued.

Yukimura Aguri was no ordinary woman despite how ditzy she acted. She had great intelligence as he had seen in her eyes but she never seemed to let it out even as they got to know each other better. She was wonderfully kind and loved to smile but there were times where he felt like she too was hiding behind a mask. He never pointed it out loud though in fear ( _ha! He was no coward but even still-_ ) that she would leave him.

He appreciated her whole presence with him.

She never failed to make him smile.

She was the closest to ever been in his heart.

And then he noticed something different.

There had been a drastic change with how the bastard (Yanagasiwa) treated her. He acted apathetically towards her, like he was trying his best to ignore her presence. He suddenly... _feared_ her. It was interesting.

"Oh right! Check out the new undershirt I bought today!" She called out to him as he was busy reading something. He turned and then stood up, walking towards her. She removed her white coat, to reveal - "Ta -da! An ogre-patterned tube top!" She grinned. "It's a tad tight, but way stylish, right?"

His gaze went towards her cleavage and in a fit of moment, he lost control of his emotions and smiled rather pervertedly at her. She blushed and pulled up her top. "I knew it," she mumbled embarrassingly. "It's weird, isn't it?"

He looked away, diverting his attention away from her chest but still protesting that it was actually cute on her. She simply laughed and giggled at how his hands - now, tentacles - started moving wildly; she commented on how it was honest and started telling him how he would have been if he had been born in a peaceful environment.

* * *

Months passed and she suddenly presented something to him in front of him. It was a black tie, handmade from what he observed. It was quite well made for someone who seemed so clumsy. He smiled at the nice thought but wondered why she was giving it to him.

"How silly, Shi-chan! I made this for you because I appreciate you. You, who had been my rock for so long, deserves at least something like this." She smiled brightly. "It never hurts to say that this is also a gift of appreciation for you having been born. Today marks a year since I met you. If you don't know when your birthday is, I thought, why not make it today?"

"As my thanks for meeting you, please let me give you a birthday."

"I'll gladly take it." He said with a smile.

Her hand made its way towards the window. His heart clenched as he heard her say sadly that she wished that she could hand her present over and touch him. She began to talk of how the bastard wanted her to quit her teaching job and work here full-time in the research laboratory. She talked of how she failed her students in terms of being a teacher but told him rather stubbornly of their good qualities. He could tell that she loved her job and the children she taught.

Her head suddenly drooped down as she silently wept.

He reached out his towards the window, as if he was touching hers. Thin versions of his tentacles wormed its way through the small holes of the glass that blocked them from touching each other. It slowly formed into a hand that gently touched her cheek. She looked up, surprised, and smiled sadly, her tears stopping.

"It's alright. You can do it." He told her.

"Thank you." She murmured as shyly touched the tentacles which formed the hand touching her cheek.

* * *

 **Escape**

* * *

The moon suddenly exploded, leaving only thirty percent of it in space which formed a very thin version of a crescent moon. I passed by the main room and over heard Yanagasiwa sprouting off things of how he would have Shi-chan killed. I let out a silent sigh as I walked slowly towards his door.

 _This is it._ I thought.

I had the door opened and told Shi-chan what I overheard. He accepted the fact quite calmly but would fight against it. He looked at me and then bid me goodbye. I begged him not to resort to evil things but he ignored what I said. He broke the glass, preventing me from seeing what was happening inside and told me to leave so that I would not die a pointless death.

He may have insulted me so that I would not die but there was no way I was leaving.

It was painful hearing him say those things but I endured. If I could endure all those abuse from Yanagasiwa, then I could certainly endure what Shi-chan verbally hurled towards me.

I left the room but instead of the main room where canon Aguri headed, I went to another room. It was a small office where I kept some things inside. I headed towards my secret compartment and opened it, to reveal a vial of something I had worked so hard on to refine on my own. I wasn't a genius scientist for nothing.

I took an empty syringe that laid right beside the vial inside the box and then injected it to my skin, straight to my bloodstream after filling it with the anti-matter from the vial. I immediately fell due to the enormous pain I felt but I fought against it stubbornly. This pain was nothing to what I could achieve with its power. The pain soon receded but then the building shook.

It had begun, Shi-chan's massacre.

I stood up slowly from my spot on the floor and then left the room. On my way, I had encountered Akari-chan, my younger sister. Her eyes widened in surprise as soon as she saw me. "Onee-chan!" She cried out. "We should leave at this moment! There was an explosion so I rushed straight into the building so that I could come get you!"

I smiled and ruffled her hair. "Akari-chan, I'm sorry but I can't leave yet. I have something I must do." And when the debris began falling, I pushed her aside so that she wouldn't get hit and still be able to make it outside.

"I'll see you again soon." I murmured.

And then I blacked out.

* * *

 **Saved**

* * *

By the time I woke up, I had noticed Shi-chan's large figure bending down. I took slow steps so that I could reach him without aggravating my wounds too much. He looked vengeful in a rather calm manner. The moon shone on his white tentacly (if that was even a word) figure, he was beautiful. I thought in awe.

"I'll die in a year regardless."

His words pulled me out of my awe-struck.

"I don't care if I die here."

 _I need to change his mind!_

"And I don't mind dying with the earth, either."

 _He was not meant to continue on this evil path!_

 _I must stop him!_

"No!"

I jumped after his figure, wrapping my arms securely over his waist. "If you go that way, there's...there's no coming back!" I shouted, trying to stop him. I could feel tears forming in my eyes as I said this. He was one of my most precious people, I couldn't let him go this way!

And then something flew straight through my gut, it was something I expected to happen but was too surprised to react properly. I rolled downwards where Shi-chan moved so quickly in order to catch me. "Aguri!" He called out my name in desperation.

I couldn't help but joke about my death regardless of how canon it was.

"Why?"

And I told him my - Aguri's - _our_ answer. It was the same no matter what. It wasn't his fault and I would do it just the same. He was someone I... _loved_ so much that I would gladly die for him. He was _that_ important to me.

I suddenly coughed out blood much to his shock.

 _Wait, I still have something else to say!_

"In this year you have left..." I began. "...if you would give your time...go teach those children...Like you...they're wandering in the darkness..."

And then there was another cough of blood. His grip on me tightened.

"If you look at them head on, I'm sure..." I grabbed a tentacle that was holding onto my person and complimented on how splendid they were. I told him that he would be a splendid teacher regardless of how he looked at the moment. I reached out for his cheek with my hand just lie he did for me before and spoke my parting words.

"..I love you, Shi-chan _...I'm sure we'll see each other again..._ "

And then my hand fell down to the side, I had lost strength.

And then I died.

* * *

 **Awakening**

* * *

\- Or not yet at least.

I was inside a white room, I noted as I sat upright. There were wires plugged to my body in order to do some readings on what was going on with my body. I paused.

 _My body..._

The door suddenly slid open to reveal an older man wearing an army uniform. I beamed once I recognized him.

"General Takumi! It's nice to see you again!" I greeted happily.

He face-palmed and shook his head. "Why do I even bother - ?" He muttered under his breath. His stance suddenly straightened and his tone became serious as he faced me. "Aguri-san, do you know why you're here?" He asked.

"Yes." I nodded slightly. "It is because I managed to survive despite having an extensive injury. It was improbable that I would survive but I did survive regardless."

"And there's also the fact that your hair has become some sort of tentacles." He added. "Your injuries had healed in only in the span of three days. I am amazed that it actually worked though. I was expecting to retrieve your dead body in the middle of all the building debris."

I simply giggled.

"Were you able to prepare everything?" I suddenly asked.

He nodded. "Yes, everything has been prepared at your disposal."

"Thank you."

A grin appeared on his face.

"Then pay me back with your hard work."

I laughed.

* * *

 **Patience  
**

* * *

I watched from the sidelines as Shi-chan - now named as Koro-sensei, taught my ex-students in his own way. It was a grueling process since I so desperately wanted to join them but stopped myself in the end. It was hard.

But with everything going on in the lab, I was already pretty close to my desired goal.

 _This will change everything._

Although I felt pretty conflicted.

 _What if it won't work?_

But - nothing.

I needed to get my mind out of the gutter. I could see them once everything ended.

In the end, it was a contest of patience.

So I waited patiently while watching as each scene unfolded in front of my eyes through the screens.

* * *

 **Return**

* * *

"This has truly... _truly_ been an unforgettable fantastic year." Koro-sensei told his students in a joyous tone.

 _I wish you all the best._

"I must be the luckiest man in this world." He told them, "To have the privilege of being assassinated by all of you..."

 _From departee to departees...This is my lifetime's worth of a final push!_

He watched immobile as Nagisa readied his knife but it wouldn't do to be killed in such a state so he calmed the blunette down. He encouraged him to be calm and steady. He had already accepted it from the start so he wanted a swift death at least. Nagisa's nervous state soon became calm and he watched the student give him a smile as the knife was readied once again.

He was prepared.

But then something changed.

The anti-sensei knife ended up hitting another tentacle, one not of his.

All of them were shocked. They turned to look at the side as a dark silhouette emerged from the shadows. It had a feminine figure with tentacles waving around it from its head. Once the person's face was revealed, they were dumbfounded.

 _Impossible!_

It was a face belonging to the deceased Yukimura Aguri!

Tears that he couldn't control began to fall from his tiny eyes. It was in that moment that he had let his guard down that another tentacle from the woman holding a syringe stabbed him straight to his heart. It was so sudden that no one, even him, could react properly.

There was a sudden pain that went through his body. It was so painful that even he, the one who had once been the God of Death, couldn't bear it that he screamed so loud. There was a bubbling sensation. He could feel that something in his composition was changing once again.

* * *

Nagisa and the rest of Class-E were instantly on guard.

This woman in front of them stopped them from killing their precious sensei and even took their kill from them!

They undoubtedly recognized her face as their previous sensei who had died according to Koro-sensei's story so why on earth would he still be alive? Was it possible that someone was sick enough to actually use the face of someone they knew that their current teacher had loved?!

They watched her cautiously as she approached. Much to their surprise, she suddenly stopped once she was close enough and raised her hands - together with all her tentacles - indicating her surrender to them.

"Hey! Why are you using our previous sensei's face?! Do you have a grudge against Koro-sensei or something to use that as a distraction to kill him?!" Terasaka shouted in anger.

She gave a gentle smile and shook her head.

"Look." She pointed towards their fallen sensei.

* * *

Koro-sensei felt different.

He opened his eyes to find all his students surrounding him with relieved smiles on their faces. There was also shock and confusion in their eyes but with relief all the same.

And then the familiar figure of Aguri entered his sight.

"Aguri!" He cried out as he sat upright, knocking some of his students down in the process. He quickly helped them up and apologized before turning his attention back to her.

"It's been too long, Shi-chan." She told him with longing shown in her eyes.

"Aguri." He said her name calmly as he rushed to hug her. To envelop her in his arms. To feel that she was not a dream-figure or a hallucination he had conjured. Her hugging him back gave him hope that it was indeed her.

But then he noticed the change.

Normally, he would be way taller her that his height and his width over tower her completely, but the thing was...he was human sized!

He wriggled his tentacles, still feeling it. Aguri beamed at him in his arms and pointed towards his hair. "I had a feeling that you might not want to part with the tentacles just yet so I let them stay. The formula I concocted was enough to reverse the process of your whole transformation but still left you tentacles intact. I hope you like it." She explained.

"H-h-how are you still alive?!"

She pouted. "Meanie, I did say that I would see you soon, right?"

"But that was when you were in the brink of death! How could you have survived th - " His words trailed off as the pieces fit together in his mind. "Y-you..."

"Yes, I plunged several anti-matter vials into my bloodstream throughout the whole year I spent with you. It was enough to heal my body once I was nearly dead. Actually, I _did_ die but only for a few minutes before the anti-matter cells in my body regenerated everything. And then I was alive again. It was a huge gamble considering that I still had things I wanted to do and people I still wanted to see before I died."

She paused and then let out a sigh.

"I'm glad it worked though."

Her attention went towards her sister, Akari, who was looking at her as if she couldn't believe that she was truly there in front of them. Aguri simply opened her arms as Kayano - formerly known as Akari - jumped in to hug her.

"I missed you so much, Onee-chan!"

Aguri patted her head gently.

"I missed you too, Akari-chan."

"WAIT! What about the laser?!" Okajima yelled out and the rest of his students began to panic.

* * *

 **Reason**

* * *

"Don't worry guys, it's all been handled." I said to appease their worries.

Just in time, the barrier and the laser were turned off. They looked at me for a moment before hugging each other and jumping in joy.

"YES!" All the students cheered.

Karasuma-san and Irina-san walked over towards me and Koro-sensei. They looked happy but had still this I'm-dying-of-curiosity look on their faces. I opened my mouth and began to explain. "You see, I have a friend in the military. He's pretty high in the hierarchy, that is why I was able to get away with everything that had transpired at this very moment." I told them.

"If you had that tentacle power in the beginning, why on earth didn't you help the octopus win the fight against that Shiro bastard and that ex-pupil of his?" Irina-san asked, definitely in an annoyed tone.

I willed my tentacles to land on my open hand. "These tentacles, once they asked me what I wanted. I had answered: _I want to have the ability to save others and to save myself._ Besides, I had no experience in combat so even if I tried to help, I would only be getting in Shi-chan's way. It was for the best that I remained hidden until the end." I explained.

The couple nodded in acknowledgment and then silence ensued... _until Akabane Karma and Nakamura Rio talked._

"Ooh~ Koro-sensei, you look pretty human now. Since Yukimura-sensei is still alive, are you planning on marrying her?" They both asked with devilish grins on their faces.

I blushed deep red of course. It was true that I loved him but I didn't know what he felt for me at all. I glanced at him and saw him spluttering weird excuses but then he stopped. He looked at me and then asked me.

 _"This is probably sudden and we've just met after such a long time but...will you marry me?"_

I promptly fainted after that.

I might have been prepared for other things but even my heart couldn't handle something like that out of the blue.

* * *

 **Killing Time**

* * *

 _Seven years have passed since the incident where Koro-sensei was saved and Yukimura Aguri was revealed to be still alive._

I walked hand-in-hand with Shi-chan as we headed to isolated mountain top right beside the school which had once been known as the Kunugigaoka Junior High School building. Once the old Class-E building was in sight, we stopped and I stared at him.

"Shi-chan, I wonder how's everyone doing?" I asked.

He smiled back to me. "I'm sure they're doing fine. We should hurry up though, I want to see how well they've doing. Nururufufu." He said.

I simply laughed as I pulled him forwards.

This was our moment.

Our killing time.

* * *

 **END**

* * *

 **A/N: Alright guys! I just finished another drabble oneshot version of a story once again! It was stuck in my head for quite some days so I wanted to just type it out and post it. I hope you enjoyed it!**


End file.
